NASA’S HUBBLE TO BEGIN SEARCH BEYOND PLUTO FOR A NEW HORIZONS MISSION TARGET
From the News Desk of Jeanne Hambleton
Embargo expired: 16-Jun-2014 11:00 AM EDT
Source Newsroom: Space Telescope Science Institute (STScI)
Newswise — After careful consideration and analysis, the Hubble Space Telescope Time Allocation Committee has recommended using Hubble to search for an object the Pluto-bound NASA New Horizons mission could visit after its flyby of Pluto in July 2015.
The planned search will involve targeting a small area of sky in search of a Kuiper Belt object (KBO) for the outbound spacecraft to visit. The Kuiper Belt is a vast debris field of icy bodies left over from the solar system’s formation 4.6 billion years ago.
Kuiper Belt object — a city-sized icy relic left over from the birth of our solar system. The Sun, more than 4.1 billion miles (6.7 billion kilometers) away, shines as a bright star embedded in the glow of the zodiacal dust cloud. Jupiter and Neptune are visible as orange and blue “stars” to the right of the Sun. A KBO has never been seen up close because the belt is so far from the Sun, stretching out to a distance of 5 billion miles into a never before-visited frontier of the solar system.
“I am pleased that our science peer-review process arrived at a consensus as to how to effectively use Hubble’s unique capabilities to support the science goals of the New Horizons mission,” said Matt Mountain, director of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.
The full execution of the KBO search is contingent upon the results from a pilot observation using Hubble observations provided by Mountain’s director’s discretionary time.
The space telescope will scan an area of sky in the direction of the constellation Sagittarius to try and identify any objects orbiting within the Kuiper Belt. To discriminate between a foreground KBO and the clutter of background stars in Sagittarius, the telescope will turn at the predicted rate that KBOs are moving against the background stars. In the resulting images, the stars will be streaked, but any KBOs should appear as pinpoint objects.
If the test observation identifies at least two KBOs of a specified brightness, it will demonstrate statistically that Hubble has a chance of finding an appropriate KBO for New Horizons to visit. At that point, an additional allotment of observing time will continue the search across a field of view roughly the angular size of the full Moon.
Astronomers around the world apply for observing time on the Hubble Space Telescope. Competition for time on the telescope is extremely intense and the requested observing time significantly exceeds the observing time available in a given year.
Proposals must address significant astronomical questions that can only be addressed with Hubble’s unique capabilities and are beyond the capabilities of ground-based telescopes. The proposals are peer reviewed annually by an expert committee, which looks for the best possible science that can be conducted by Hubble and recommends to the STScI director a balanced program of small, medium, and large investigations.
Though Hubble is powerful enough to see galaxies near the horizon of the universe, finding a KBO is a challenging needle-in-haystack search. A typical KBO along the New Horizons’ trajectory may be no larger than Manhattan Island and as black as charcoal.
Even before the launch of New Horizons in 2006, Hubble has provided consistent support for this edge-of-the-solar system mission. Hubble was used to discover four small moons orbiting Pluto and its binary companion object Charon, providing new targets to enhance the mission’s scientific return.
And Hubble has provided the most sensitive search yet for potentially hazardous dust rings around Pluto. Hubble also has made a detailed map of the dwarf planet’s surface, which astronomers are using to plan New Horizons’ close-up reconnaissance photos.
In addition to Pluto exploration, recent Hubble solar system observations have discovered a new satellite around Neptune, probed the magnetospheres of the gas-giant planets, found circumstantial evidence for oceans on Europa, and uncovered several bizarre cases of asteroids disintegrating before our eyes.
Hubble has supported numerous NASA Mars missions by monitoring the Red Planet’s seasonal atmospheric changes. Hubble has made complementary observations in support of the Dawn asteroid mission, and comet flybys. Nearly 20 years ago, in July 1994, Hubble documented the never-before-seen string of comet collisions with Jupiter that resulted from the tidal breakup of comet Shoemaker-Levy 9.
“The planned search for a suitable target for New Horizons further demonstrates how Hubble is effectively being used to support humankind’s initial reconnaissance of the solar system,” said Mountain.
“Likewise, it is also a preview of how the powerful capabilities of the upcoming James Webb Space Telescope will further bolster planetary science. We are excited by the potential of both observatories for ongoing solar system exploration and discovery.”
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.
RESEARCHER SHOWS HOW STRESS HORMONES PROMOTE BRAIN’S BUILDING OF NEGATIVE MEMORIES
Important clinical implications for understanding PTSD and memory in women
From the News Desk of Jeanne Hambleton
Released: 23-Jul-2014 12:00 PM EDT
Source Newsroom: Arizona State University College of Liberal Arts and Sciences – Citations Neuroscience
Newswise — When a person experiences a devastating loss or tragic event, why does every detail seem burned into memory; whereas, a host of positive experiences simply fade away?
It’s a bit more complicated than scientists originally thought, according to a study recently published in the journal Neuroscience by Arizona State University researcher Sabrina Segal.
When people experience a traumatic event, the body releases two major stress hormones: norepinephrine and cortisol. Norepinephrine boosts heart rate and controls the fight-or-flight response, commonly rising when individuals feel threatened or experience highly emotional reactions. It is chemically similar to the hormone epinephrine – better known as adrenaline.
In the brain, norepinephrine in turn functions as a powerful neurotransmitter or chemical messenger that can enhance memory.
Research on cortisol has demonstrated that this hormone can also have a powerful effect on strengthening memories. However, studies in humans up until now have been inconclusive – with cortisol sometimes enhancing memory while at other times having no effect.
A key factor in whether cortisol has an effect on strengthening certain memories may rely on activation of norepinephrine during learning, a finding previously reported in studies with rats.
In her study, Segal, an assistant research professor at the Institute for Interdisciplinary Salivary Bioscience Research (IISBR) at ASU, and her colleagues at the University of California- Irvine showed that human memory enhancement functions in a similar way.
Conducted in the laboratory of Larry Cahill at U.C. Irvine, Segal’s study included 39 women who viewed 144 images from the International Affective Picture Set. This set is a standardized picture set used by researchers to elicit a range of responses, from neutral to strong emotional reactions, upon view.
Segal and her colleagues gave each of the study’s subjects either a dose of hydrocortisone – to simulate stress – or a placebo just prior to viewing the picture set. Each woman then rated her feelings at the time she was viewing the image, in addition to giving saliva samples before and after. One week later, a surprise recall test was administered.
What Segal’s team found was that “negative experiences are more readily remembered when an event is traumatic enough to release cortisol after the event, and only if norepinephrine is released during or shortly after the event.”
“This study provides a key component to better understanding how traumatic memories may be strengthened in women,” Segal added. “because it suggests that if we can lower norepinephrine levels immediately following a traumatic event, we may be able to prevent this memory enhancing mechanism from occurring, regardless of how much cortisol is released following a traumatic event.”
Further studies are needed to explore to what extent the relationship between these two stress hormones differ depending on whether you are male or female, particularly because women are twice as likely to develop disorders from stress and trauma that affect memory, such as in Posttraumatic Stress Disorder (PTSD).
In the meantime, the team’s findings are a first step toward a better understanding of neurobiological mechanisms that underlie traumatic disorders, such as PTSD.